1. Field of the Invention
The present invention relates to a surrounding light judging method and a video compensation control apparatus using the same, and in particular to an improved surrounding light judging method and a video compensation control apparatus using the same which are capable of providing an optimum viewing quality by automatically correcting video data in accordance with a surrounding lighting environment of a video displaying instrument.
2. Description of the Conventional Art
Generally, a color adaptation phenomenon is defined as a phenomenon where an original color is recognized by human eyes as another color because the human eyes are made adaptive by a predetermined light such as an incandescent light, a fluorescent light, etc.
Therefore, a television viewer may recognize the colors reproduced by a color picture tube as other colors by the above-described color adaptation phenomenon, so that it is impossible to enjoy the optimum quality of colors. Thus, video data is corrected based on the surrounding light environment using a video correction (compensation) apparatus to provide an optimum quality of colors.
As shown in FIG. 1, the conventional video compensation apparatus includes an RGB sensor 10 for detecting RGB data based on the surrounding environment, a key selector 20, a microcomputer 30 for summing RGB data detected by the RGB sensor 10 and outputting a video compensation data corresponding to the summed value, and a combined video signal processor 40 for processing a combined video signal received through the antenna and recovering a video signal and an audio signal.
The combined video signal processor 40 includes a tuner 11 for selecting a predetermined channel, an IF processor 12 for converting the combined video signal of the selected channel into an intermediate frequency signal, a detector 13 for detecting an intermediate frequency signal from the IF processor 12 and separating the detected intermediate frequency signal into a video intermediate frequency signal and an audio intermediate frequency signal, an audio processor 14 for recovering the audio intermediate frequency signal from the detector 13 and outputting the recovered signal to a speaker 15, and a video processor 16 for recovering the video intermediate frequency signal from the detector 13 to an RGB signal in accordance with the video compensation data output from the microcomputer 30.
The operation of the conventional video compensation apparatus will now be explained with reference to the accompanying drawings.
First, after the television is turned on using the key selector 20, when a predetermined selection key is inputted, the microcomputer 30 outputs a channel selection data based on the output from the key selector 20.
In addition, the microcomputer 30 receives an RGB data with respect to the surrounding environment detected by the RGB sensor 10, sums the RGB data (S=DR+DG+DB), compares the previously set control data table shown in FIG. 2A with the sum value S of the RGB data, judges the surrounding light level and sets a control data and a W/B (White/Balance) corresponding to the judged surrounding light level.
Namely, as shown in FIGS. 2A and 3A, when the sum value (S) is 0xe2x89xa6Sxe2x89xa62, the microcomputer 30 judges the surrounding environment as a dark room, sets the control data as Contrast=30, Brightness=40, Saturation=40, and sharpness=30, and performs a first compensation step in Steps S3 and S4. When the sum value S is 2xe2x89xa6S less than 45 as in Step S5, the control data based on the sum value S is set, and the second through sixth compensation steps are performed as shown in Steps S5 through S14 of FIG. 3A.
In addition, when the sum value S is 45xe2x89xa6S, the microcomputer 30 judges the surrounding light as a daylight sets the control data as Contrast=100, Brightness=60, Saturation=55 and sharpness=60, and performs a seventh compensation step as in Step S15.
More particularly, in the first through seventh compensation steps, the microcomputer 30, as shown in FIGS. 2B and 3B, judges that the surrounding light corresponds to a dark room light when the sum value S is S less than 2, sets the W/B to 9000xc2x0 K in Steps S20 through S23. When the sum value S is Sxe2x89xa745, the surrounding light is judged as a daylight, and then the W/B is set as 1300xc2x0 K in Steps S24 and S25. When the sum value S is 2xe2x89xa6S less than 45, the W/B is set in accordance with the subtracted value between R and B in Step S26.
Namely, when the subtracted value S1 is S1xe2x89xa60, the surrounding light is judged to be a fluorescent lamp, and then the W/B is set as 12000xc2x0 K in Steps S27 and S28. When the subtracted value is S1xe2x89xa65 the surrounding light is judged to be a fluorescent light and an incandescent lamp, and the W/B is set to 11000xc2x0 K in Steps S29 and S30. When the subtracted value is S1xe2x89xa75, the surrounding light is judged to be an incandescent lamp, and the W/B is set to 1000xc2x0 K in Step S31.
The control data and W/B determined by the microcomputer 30 based on the detected surrounding light, as described above, are used to adjust video signals prior to being displayed on the tube 17. For example, the tuner 11 selects a predetermined channel in accordance with the channel selection data from the microcomputer 30, and the IF processor 12 converts the combined video signal of the selected channel into an intermediate frequency signal. The detector 13 separates the converted intermediate frequency signal into a video intermediate frequency signal and an audio frequency signal.
Consequently, the separated audio intermediate frequency signal is recovered to an audio signal by the audio processor 14 and outputted to the speaker 15. The video processor 16 receives a video intermediate frequency signal from the detector 13, compensates the video signals in accordance with the video compensation data set by the microcomputer 30 and the W/B, and displays the compensated video signals on the color picture tube 17.
However, in the conventional video compensation apparatus, when the brightness of the surrounding light is decreased, the sum value S is decreased. Then, the brightness of the surrounding light may be erroneously detected due to the low sum value S, which can cause a malfunction in the system.
In addition, when the brightness of the surrounding light reaches a certain high value, for example, Sxe2x89xa746, the microcomputer 30 sets the W/B to 13000xc2x0 K regardless of how high S may be. In this manner, it is impossible to accurately set the W/B based on the judged brightness, especially when the sum value S is high.
Furthermore, in the conventional video compensation apparatus, since the color adaptation phenomenon is not considered, it is impossible to secure a quality picture.
Accordingly, it is an object of the present invention to provide a surrounding light judging method and a video compensation control apparatus using the same which overcome the aforementioned problems encountered in the conventional art.
It is another object of the present invention to provide an improved surrounding light judging method and a video compensation control apparatus which are capable of providing an optimum quality of picture by detecting a color signal near a video displaying instrument, judging a lighting environment from the detected color signal, and automatically correcting video data in accordance with the judged lighting environment and a variation in the lighting environment.
To achieve the above and other objects, there is provided a surrounding light judging method which includes the steps of detecting a first color component and a second color component from a surrounding light, and judging a kinds of the light using the first and second color components.
Additional advantages, objects and features of the invention will become more apparent from the description which follows.